Water filters are commonly used to remove contaminants from or to purify drinking water. Filters may employ a variety of methods to remove contaminants, including sieving, adsorption, ion exchanges, biological metabolite transfer and other processes. Other devices, such as sieves and screens, are also used to remove larger contaminants or particles from water by physically preventing the contaminants from passing through the screen or sieve. Filters differ from sieves or screens, as filters can remove particles that are much smaller than the holes through which the water passes when using a sieve or a screen device.
Filters may be employed both at water treatment facilities and at the actual point of use for the water, such as in the home. Point-of-use filters may be installed on a faucet or in a container such as a pitcher or a bottle. Point-of-use filters may utilize one or more of a variety of techniques or components to remove various contaminants, including: granular-activated carbon filters (“GACs”) for filtering out chlorine and organic compounds; metallic alloy filters; microporous ceramic filters; carbon block resin (“CBR”) filters; ion exchange resins; microfiltration; and ultrafiltration membranes.
In particular, pitchers incorporating point-of-use filters may incorporate two chambers: an upper chamber or reservoir for holding unfiltered water prior to filtration and a lower chamber or reservoir for holding filtered water prior to use. The two chambers are separated by a filter. When the upper reservoir is filled with water, gravity forces the water to travel down through the filter and into the lower reservoir. Once the lower reservoir is full, any additional water in the upper reservoir remains there until water is drained from the lower reservoir. Generally, such pitchers include a channel leading from the lower reservoir to a spout through which filtered water may be poured. An example of this type of water pitcher and filter is found in U.S. Pat. No. 8,043,502, the disclosure of which is incorporated herein by reference in its entirety.
However, conventional water pitchers employing conventional filters suffer from several disadvantages. Commonly, the structure and arrangement of the pitcher and filter prevent all the water in the upper reservoir from flowing through the filter. For example, using conventional designs, the filter cartridge must be sized and shaped precisely so as to fit within a predefined receptacle in the water pitcher. As a result, each filter cartridge may be used with only a single model or brand of water pitcher. Using a filter cartridge that does not meet the exact dimensions of the receptacle results in several disadvantages.
First, an inexact fit between the filter cartridge and the receptacle may prevent the upper reservoir from entirely “emptying out” through the filter. In such cases, a significant amount of water (for example, up to a quarter of an inch) may remain standing in the upper reservoir and not enter the filter cartridge because the top of the filter cartridge is not precisely aligned with the lowest portion of the upper reservoir. This is relatively inefficient, as water that does not pass through the filter may not be used. Further, as water in the upper reservoir evaporates, contaminants may build up in the upper reservoir, requiring the upper reservoir to be cleaned more frequently. If organic compounds are present in the water, bacteria or other organisms may thrive in the standing water in the upper reservoir.
Second, the cartridge may not sit properly in the receptacle in the upper reservoir, such that the cartridge walls do not completely seal against the receptacle walls, thereby allowing unfiltered water to flow around the cartridge and enter the lower reservoir without first passing through the filter. This causes the water in the lower reservoir to become contaminated with any particulates or chemicals that are present in the water prior to filtration, thereby negating some or all of the benefits of using a filter.
Conventional pitchers commonly employ replaceable filter cartridges. These filter cartridges must be entirely replaced once the filter(s) they contain have worn down or degraded, for example due to the buildup of contaminants in the filter cartridge. This creates needless waste, as the filter cartridge itself is still perfectly functional. Conventional replaceable filter cartridges, such as that disclosed in U.S. Patent Publication No. 2011/0303618 (the contents of which are incorporated fully herein by reference), attempt to address this problem by allowing filters to be replaced without disposing of the filter cartridge as a whole. However, such conventional designs generally exacerbate the other drawbacks discussed above.
The disadvantages of current container and filter assemblies outlined above, among other things, are overcome by a new design of filter cartridge and closure system.
Therefore, there is a need in the art for a new design of a water filter cartridge and closure system that overcomes the disadvantages of the prior art and provides the advantages as described in this disclosure.